The left 8 represents 8000 units. The right 8 represents 8 units.
Their placement in the number is used to signify the multiplier for the number of units they represent. That is why the number system is called a "place value number system." Each time the digit is moved left one place, its value increases by a factor of 10.
As first term in sequence is 3 so multiplying it by common ratio 5 we get 15, then multiplying 15 by 5 we get 45 and so on the sequence is <span>3,15,45,225</span> whose sum is 288
